The present invention relates to a process for preserving compositions, such as cosmetic and dermatological compositions, which may be intended for topical applications, through the use of certain polyamino acid derivatives.
It is common practice to introduce chemical preserving agents into cosmetic and dermatological compositions, these agents intended to combat the growth of microorganisms in these compositions, which would quickly make the cosmetic and dermatological compositions unsuitable for use. It is especially necessary to protect cosmetic and dermatological compositions against the microorganisms liable to grow inside the compositions and also against those which the user might introduce while handling it, such as when taking up products in jars with the fingers. Chemical preserving agents that are commonly used include parabens and formaldehyde-releasing compounds. However, these preserving agents have a drawback of causing irritation, in particular on sensitive skin, when they are present in relatively large amounts. Other known preserving agents which may be mentioned include organic hydroxy acids. However, these compounds may also cause irritation on account of their desquamating effect on the skin, which is not always well tolerated.
Thus there is a need for preserving agents, such as antimicrobial agents, whose activity is at least as effective as that of the compounds of the prior art, but which do not possess all of the drawbacks of the prior art compounds. Moreover, it would be desirable to make available antimicrobial agents whose antimicrobial spectrum is at least as broad, if not broader, than that of the compounds already known.
One aim of the present invention is thus to propose preserving agents which have a broad antimicrobial spectrum, but which do not possess all of the drawbacks of the prior art.
One subject of the present invention is the use of at least one compound chosen from polyamino acid derivatives corresponding to formula (I) as defined below, and salts thereof, as a preserving agent.
Another subject of the invention is a process for preserving a composition, such as a cosmetic or pharmaceutical composition, comprising introducing at least one polyamino acid derivative of formula (I) as defined below into the composition.
Another subject of the invention is a cosmetic and pharmaceutical composition comprising, in a physiologically acceptable medium, at least one preserving agent chosen from polyamino acid derivatives of formula (I) as defined below and salts thereof.
It has thus been found, surprisingly and unexpectedly, that certain polyamino acid derivatives may have good antimicrobial properties with respect to, for example, viruses, bacteria, yeasts and fungi/molds. On account of their broad antimicrobial spectrum, these derivatives may thus be used, for example, in cosmetic compositions as sole antimicrobial agents, such as antibacterial agents, as antiviral agents, as anti-yeast agents and as antifungal agents. Moreover, these polyamino acid derivatives may be advantageously used as preserving agents in cosmetic and pharmaceutical compositions, such as dermatological compositions.
Advantages of the polyamino acid derivatives according to the present invention, which may be based on their clearly defined and characterized chemical structure, include their manufacture being readily reproducible, and their industrial feasibility being relatively simple. Furthermore, the polyamino acid derivatives according to the present invention have good solubility and compatibility with the media commonly used in cosmetics, for example, aqueous media.
The polyamino acid derivatives used in the context of the present invention are well known in the prior art, including the cosmetics art for their moisturizing properties and for their use in haircare.
Mention may thus be made of Japanese patent application JP-07/041 467, which discloses a class of polyamino acids of high molecular weight consisting essentially of cysteine, as well as the process for preparing these polyamino acids. A class of polyamino acids characterized by the presence of thiol and disulphide functions has also been disclosed in Japanese patent application JP-06/248 072. These polyamino acids react with the thiol linkages of keratin, thus forming disulphide bridges, which makes it possible to increase the sheen and coloration qualities of the hair. Polyamino acids consisting essentially of amino acids with neutral and acidic chains have been disclosed in Japanese patent application JP-04/198 114, along with their use as moisturizing agents.
Mention may also be made of patent application FR-A-2 776 510, which discloses a cosmetic composition intended for reinforcing and caring for keratin fibres, in particular hair fibres, comprising polyamino acid derivatives.
The polyamino acid derivatives used in the context of the present invention correspond to formula (I) below: 
in which:
X is chosen from O, S, NH and NRxe2x80x3, wherein Rxe2x80x3 is chosen from saturated and unsaturated, linear and branched C1-6 hydrocarbon-based radicals;
R1 is chosen from,
i) linear and branched, saturated and unsaturated C1-40 hydrocarbon-based radicals, optionally substituted with at least one hydroxyl radical and at least one radical xe2x80x94NRRxe2x80x2 and optionally interrupted with at least one hetero atom chosen from N, O and Si, wherein R and Rxe2x80x2, which may be identical or different, are chosen from hydrogen and saturated and unsaturated, linear and branched C1-6 hydrocarbon-based radicals;
ii) radicals of the formula 
wherein s may be equal to 0, 1, 2, 3 and 4; and R4 is chosen from hydrogen and radicals chosen from xe2x80x94NH2, xe2x80x94OH, xe2x80x94SH, xe2x80x94CHOHCH3, xe2x80x94CONH2, xe2x80x94NHxe2x80x94C(NH2)xe2x95x90NH, xe2x80x94C6H5, xe2x80x94C6H4OH, 
iii) radicals of the formula 
wherein m may be equal to 3, 4 and 5;
R2 is chosen from hydrogen; saturated and unsaturated, linear and branched C1-8 hydrocarbon-based radicals; radicals chosen from xe2x80x94CH2C6H5, xe2x80x94CH2C6H4OH, xe2x80x94CH2OH, xe2x80x94CHOHCH3, xe2x80x94(CH2)txe2x80x94NH2 wherein t may be equal to 3 and 5;
R3 is chosen from hydrogen and saturated and unsaturated, linear and branched C1-6 hydrocarbon-based radicals;
n is an number greater than 1 such that the number average molecular weight of the polyamino acid derivative generally ranges from 100 to 200 000;
wherein the repeating units may be identical or different for the same derivative.
For example, the repeating units may be identical. If the repeating units are different, then at least one of R2 and R3 may be varied between the repeating units by choosing at least one of the other meanings given for these radicals.
The salts of the polyamino acid derivatives, such as mineral acid salts and organic acid salts, also form part of the present invention.
According to one embodiment of the present invention, at least one of the following definitions apply to the polyamino acid derivatives:
X is chosen from O, S, NH and NRxe2x80x3, wherein Rxe2x80x3 is chosen from saturated and unsaturated, linear and branched C1-6 hydrocarbon-based radicals;
R1 is chosen from linear and branched, saturated and unsaturated C8-40 hydrocarbon-based radicals, optionally substituted with at least one hydroxyl radical and one radical
NRRxe2x80x2 and optionally interrupted with at least one hetero atom chosen from N, O and Si, wherein R and Rxe2x80x2, which may be identical or different, are chosen from hydrogen and saturated and unsaturated, linear and branched C1-6 hydrocarbon-based radicals;
R2 is hydrogen;
R3 is chosen from saturated, linear and branched C1-6 hydrocarbon-based radicals; such as, for example, methyl and ethyl radicals; and
n is chosen from a number ranging from 2 to 100, or is chosen from a number such that the number average molecular weight of the polyamino acid derivative generally ranges from 150 to 10,000. In certain embodiments, each of these definitions apply.
In another embodiment of the present invention, at least one of the following definitions apply to the polyamino acid derivatives:
X is chosen from O, S and NH;
R1 is chosen from linear and branched, saturated C10-24 hydrocarbon-based radicals, optionally substituted with 1, 2, 3 and 4 hydroxyl radicals; and linear and branched unsaturated C12-24 hydrocarbon-based radicals, optionally substituted with at least one hydroxyl radical;
R2 is hydrogen;
R3 is a methyl radical; and
n is chosen from a number ranging from 4 to 50, or is chosen from a number such that the number average molecular weight of the polyamino acid derivative generally ranges from 300 to 8 000. In certain embodiments, each of these definitions apply.
The polyamino acid derivatives according to the invention may readily be prepared by those skilled in the art on the basis of their general knowledge. Patent application FR-A-2 776 510, for example, discloses a process for preparing these compounds.
The polyamino acid derivatives may be present in the compositions, such as a cosmetic and pharmaceutical composition, in an amount which is sufficient to obtain the desired effect, such as in an amount generally ranging from 0.001% to 30% by weight, for example, such as from 0.01% and 15% by weight, relative to the total weight of the composition. In one embodiment, the polyamino acid derivatives is present in the composition in an amount ranging from 0.5% to 5% by weight, relative to the total weight of the composition.
The composition comprising the polyamino acid derivatives further comprises mediums which may be cosmetically and pharmaceutically acceptable, such as. mediums which are compatible with the skin, mucous membranes, the hair and the scalp. They may be in any presentation form which is suitable for topical application. Suitable forms include aqueous, aqueous-alcoholic, organic and oily solutions; suspensions and dispersions in solvents and fatty substances; lotions and serums; vesicular dispersions; W/O, O/W, and multiple emulsions such as cream and milk; ointments, gels, solid tubes, pasty and solid anhydrous products; mousses, such as an aerosol mousse; and sprays.
The physiologically acceptable medium in which the polyamino acid derivatives may be used, and also its constituents, the amount thereof, the presentation form of the composition and the method for preparing it, may be chosen by those skilled in the art on the basis of their general knowledge depending on the desired type of composition.
For example, the composition can comprise any fatty substance usually used in the field of application envisaged. Mention may be made, for example, of silicone fatty substances such as silicone oils, gums and waxes, as well as non-silicone fatty substances such as oils and waxes of plant, mineral, animal and synthetic origin. The oils may be chosen from volatile and non-volatile oils. Mention may also be made of synthetic hydrocarbons, esters and ethers, fatty alcohols and fatty acids.
The composition can also comprise an aqueous medium, an aqueous-alcoholic medium containing an alcohol such as ethanol and isopropanol, an organic medium comprising common organic solvents such as C1-C6 alcohols, including ethanol and isopropanol, glycols such as propylene glycol, and ketones.
The composition can further comprise at least one conventional emulsifier chosen from amphoteric, anionic, cationic and nonionic emulsifiers, which may be used alone and as a mixture.
The composition can also comprise at least one adjuvant that is common in the field under consideration, such as hydrophilic and lypophilic thickeners and gelling agents, hydrophilic and lypophilic additives, active agents, such as cosmetic active agents, preserving agents, antioxidants, fragrances, fillers, pigments, UV screening agents, odor absorbers, dyes, moisturizers such as glycerol, vitamins, essential fatty acids, lyposoluble polymers, such as hydrocarbon-based polymers, opacifiers, stabilizers, sequestering agents, conditioners and propellants.
Needless to say, a person skilled in the art will take care to select the at least one adjuvant and the amount thereof such that the advantageous properties of the composition according to the invention are not substantially adversely affected by the addition envisaged.
The pH of the compositions according to the invention is generally less than 7. In one embodiment, the pH ranges from 3 to 6.
The polyamino acid derivatives used in the context of the present invention may have antimicrobial activity. In one embodiment, the antimicrobial activity is chosen from antibacterial activity, antiviral activity, antiyeast activity and antifungal activity.
Depending on the nature of the substituents X, R1, R2 and R3, and on the value of xe2x80x9cnxe2x80x9d, it has been found that it is possible to obtain compounds that are more active, and also those which are less active, with respect to a given type of microbe. The field of action of the derivatives according to the invention may thus be modified by focusing on a given microbe, and then by appropriately selecting the chemical nature of the compound used.
The polyamino acid derivatives according to the invention thus find application, for example, in compositions which may be:
in the form of make-up products for the skin of the face, of the body and of the lips, such as, for example, foundation, face powder, eye shadow, concealer sticks, cover sticks, eyeliner, mascara, lipstick, a nail varnish and a nailcare product;
in the form of dermatological and cosmetic care products for the skin of the face, of the body, including the scalp, and of the lips, such as a lipcare base, a fixing base to be applied over a conventional lipstick, antisun compositions and artificial tanning compositions; deodorant products; care compositions (day, night, anti-wrinkle, moisturizing, etc. product) for the face; matt-effect compositions for the face; cleansing and make-up-removing gel and cream; a protective body milk, a bodycare milk, and a purifying milk;
in the form of deodorant compositions; aftershave gels and lotions; and hair-removing cream;
in the form of pharmaceutical compositions;
in the form of solid composition such as cleansing soaps and bars;
in the form of aerosol compositions also comprising propellant under pressure;
in the form of haircare compositions, such as, for example, shampoo, hairsetting lotions, medicated lotions, styling creams and gel, dye compositions, such as, for example, an oxidation dye composition, optionally in the form of coloring shampoos, restructuring lotions for the hair, permanent-waving compositions, lotions and gels for preventing hair loss, antiparasitic shampoo; antidandruff lotions and shampoos; and medicated shampoo, such as an anti-seborrhoeic shampoo; and
in the form of compositions for buccodental use, such as, for example, a toothpaste.
Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term xe2x80x9cabout.xe2x80x9d Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
The present invention is illustrated in greater detail in the nonlimiting examples which follow.